DE10043433A1 - Aqueous 2-component PUR systems - Google Patents

Abstract

The invention relates to aqueous 2K PUR systems consisting of specially modified vinyl polymer polyol dispersions and polyisocyanates, to a method for producing aqueous 2K PUR systems of this type with improved resistance to aqueous chemicals and to their use as 2K PUR coatings for coating any given substrates.

Description

The invention relates to aqueous 2-component PU systems made from specially modified vinyl polymer poly dispersions and polyisocyanates, a process for the preparation of sol cher aqueous 2K-PUR systems with improved stability against aqueous chemicals lien and their use as 2K-PUR-lacquers for the painting of any Substrates such as B. wood, metal, plastic.

In EP-A 0 358 979, EP-A 0 496 210 and EP-A 0 557 844 and others Patent literature describes the production of aqueous 2-component PU dispersions ben in which both so-called secondary dispersions and so-called Pri mar dispersions as polyol components for use with suitable polyisocyanas ten come. Under the term "secondary dispersions" such aqueous Understand dispersions that are initially polyme in the homogeneous organic medium be neutralized and then with neutralization generally without the addition of external Emulsifiers are redispersed in an aqueous medium.

The term "primary dispersions" is understood to mean polyol dispersions that directly in the aqueous phase by the process of emulsion polymerization be put. They generally contain external emulsifiers; effect this electrostatic or steric stabilization.

The secondary dispersions are due to their relatively low molecular weights M _n mostly less than 5000 g / mol and M _w mostly less than 30,000 g / mol and due to their balanced hydrophilic / lipophilic character, in addition to hydrophilized also hydrophobic, non-self-dispersing polyisocyanates in aqueous Mi lieu to emulsify stably and at the same time to act as a reactive component (cf. EP-A 0 358 979). Because of the relatively low molecular weights of the polyol secondary dispersions, however, such aqueous 2-component PU systems are usually unsuitable for their physical drying on wood as a substrate. The drying times (hand and dust drying) are too long and unsuitable for industrial painting.

In general, those which contain primary dispersions as polyol components are more suitable than physically fast drying aqueous 2-component PU systems. These generally have molecular weight values of M _n well above 5000 g / mol and M _w values of usually more than 30,000 g / mol. These primary dispersions can generally only be combined with (partially) hydrophilized polyisocyanates; this enables a relatively uncomplicated dispersion with simple stirring units or by hand and glass rod (cf. EP-A 0 557 844). Are now z. B. nonionically hydrophilicized with polyether groups, polyisocyanates are used as crosslinking agents and if such coatings are applied, for example, to wood as a substrate, then they are kept after they have been dried, lacquer layers which, after exposure to coloring substances such. B. red wine, coffee, tea, mustard, among other things, to retain permanent discolouration, which can lead to permanent stains in particular on furniture. In addition, such coating systems show slight film turbidity. If polyisocyanates which contain external or internal anionic groups are used as an alternative, the stain resistance improves, but the level of resistance which can be achieved is still not sufficient. Furthermore, the compatibility of the components deteriorates with one another in such systems, and the films have an increased haze.

There was therefore the technical problem of using polyol dispersions as components for To provide 2K PUR systems with polyisocyanate components that contain anionic groups, for stain-resistant and haze-free coating filmings.

This problem was solved by adding aqueous polyol dispersions, preferably of the type primary dispersions which in the presence of special nonio African surfactants have been produced with polyisocyanates that are both hydro phobic character as well as nonionic or anionically hydrophilized character  have combined. This fact was all the more surprising because, as before mentioned above, polyol dispersions without such special nonionic ten side in combination with non-ionically hydrophilized polyisocyanates to form coatings insufficient stability against aqueous coloring liquids, and one had to expect that after further addition of nonionic surfactants to the 2K-PUR system would result in even worse resistance.

The invention therefore relates to aqueous 2-component PU lacquers with improved resistance to aqueous chemicals, characterized in that the aqueous 2-component PU systems used as binders consist of

• a) vinyl polymer polyol type dispersions,
• b) polyisocyanates and
• c) usual additives for water-based paint technology

consist of
the polyol dispersions a)
Hydroxyl numbers between 10 and 264 mg KOH / g solid resin, acid numbers (calculated on the sum of the neutralized and non-neutralized acid groups) between 0 to 55 mg KOH / g solid resin, molecular weights M _n

of at least 5000 g / mol or M _w

of at least 30,000 g / mol, glass transition temperatures of at least 20 ° C and medium re have particle diameters of at most 300 nm and in the presence of

• 1. 0.1 to 10.0 wt .-%, based on the sum of the solids contents of Polymer polyol and polyisocyanate, nonionic surfactants of the polyether type have been manufactured

the polyisocyanates b)
Viscosities of at most 12000 mPa.s and have either non-hydrophilized or nonionic or anionically hydrophilized character, and wherein component b) of component a) is added in such an amount that an equivalent ratio of isocyanate groups of component b) to hydroxyl groups of the component a) from 0.2: 1 to 5: 1.

The invention also relates to a process for the preparation of such aqueous 2K PU systems.

Component a) is preferred in the presence of

• 1. 1.0 to 8.0% by weight of the non-ionic surfactant of the polyether type provides.

Preferred surfactant components a1) are block polymers of ethylene oxide and propylene oxide of the formula (I)

and / or block and statistical ethylene oxide / propylene oxide copolymers based on fatty alcohol (II),
and / or block polymers of the type according to formula (III) which can be obtained by polycondensation of propylene oxide and ethylene oxide on ethylenediamine:

and / or adducts of polyethylene oxide with fatty alcohols (IV)
and / or polyether / polyester block polymers (V) produced or used.

The surfactant classes (I), (II), (III) and (IV). These nonionic surfactants generally have a polyethylene Lenoxide content of 5 to 80 wt .-%, molecular weights up to 10000 g / mol and hydroxylge keep between 0.3 and 8.0% by weight.

Component a) is prepared in such a way that the nonionic surfactant a1) is already present or is added during the polymerization. The use of a1) is preferred before the preparation of a) in the polymer template.

The polyisocyanate component b) can both

• 1. non-hydrophilized character as well
• 2. nonionic or hydrophilic character
• 3. have an anionically hydrophilized character.

If a non-hydrophilized, water-insoluble or non-dispersible polyi Socyanate component b1) used in the aqueous 2K-PUR system is a good one Dispersing effect only by means of a highly effective dispersing unit, e.g. B. with a nozzle jet disperser according to EP-A 0 685 544 possible. Only with this  after application of the film the highest possible chemical resistance of the 2K PUR systems achieved.

However, if the polyisocyanate component b) is to be used with simpler dispersing units such as B. a dissolver or by using a 2K system with a prever dust nozzle or possibly even manually effective and finely divided with the bottom be dispersed lyol component, so is a nonionic or an anionic Hydrophilization of b) (as components b2) or b3)) is absolutely necessary.

The nonionic hydrophilization of the polyisocyanate component b) takes place in all mean by modifying an unmodified hydrophobic polyisocyanate with a polyether monoalcohol e.g. B. according to EP-A 0 540 985 and EP-A 0 959 087.

The anionic hydrophilization of component b) is preferably carried out by using from 0.2 to 5.0% by weight (based on the sum of the solids contents of polymer polyol and polyisocyanate) of sulfate, sulfonate or phosphate groups-containing surfactants to form the unmodified, hydrophobic polyisocyanate component b). The particularly preferred surfactants containing phosphate groups have the following structures:

n = 1-100; p = 5-20; r = 5-15; M = alkali or (subst.) Ammonium ion.

The sole use of phosphate-containing surfactants of the above structure in aqueous Two-component PUR systems are already known (see, for example, WO 98/38196 and WO 98/38231), but leads to the mixing of the polyisocyanate component b) with the Polyol component a) not in the presence of the nonionic surfactant component a1) has been produced, to unusable results: the polyisocyanates b) are much more difficult to incorporate into the polyol a), resulting in more unstable 2K dispersions, and the dried paint films are significantly cloudy, as in the present examples are shown; also the stability of, for example Wood as a substrate dried 2K film against aqueous chemicals such as z. B. coloring substances (red wine, coffee, tea and mustard) is significantly reduced.

The anionic hydrophilization of component b) can in addition to phosphate groups also done by sulfate or sulfonate groups. Use is preferred of sulfonate groups which are present in chemically bound form in the polyisocyanate. These can e.g. B. by the reaction of polyisocyanates with sulfonate groups containing surfactants, which additionally have at least one against NCO groups wear reactive group, be made. The sulfonate groups can  present in amounts of 0.1-5.0 wt .-%, based on the polyisocyanate his.

In principle, it is also possible to use mixed-hydrophilized polyisocyanates, as they e.g. B. is described in EP-A 0 510 438. Here there is a simultaneous Hydrophilization with nonionic polyether groups and (potentially) anionic Carboxyl groups.

The polymers a) are hydroxy-functional copolymers of the hydroxyl number range 10 to 264 mg KOH / g solid resin, the acid number range 0 to 55 mg KOH / g solid resin, which otherwise have a total content of chemically bound carboxylate and / or sulfonate groups of 0 have up to 97 mil equivalents per 100 g of solid. The acid number here relates both to the free, non-neutralized acid groups, in particular carboxyl groups, and to the neutralized acid groups, in particular carboxylate groups. The copolymers generally have a molecular weight M _{n which} can be determined by the method of gel permeation chromatography using polystyrene as the standard, from 5000 to 300,000, preferably 10,000 to 200,000 or a molecular weight M _w of 30,000 to 2,000,000, preferably from 40,000 to 500,000 g / mol on.

The copolymers a) are preferably those of

• A) 0 to 7, preferably 1 to 5% by weight of acrylic acid and / or methacrylic acid,
• B) 0 to 75% by weight of methyl methacrylate,
• C) 0 to 75% by weight of styrene, the sum of B + C giving 10 to 85% by weight,
• D) 3 to 40% by weight of one or more C _1-8 alkyl acrylates or C _2-8 alkyl methacrylates,
• E) 2 to 74% by weight of one or more monohydroxy-functional alkyl acrylates or alkyl methacrylates
• F) 0 to 15% by weight of other olefinically unsaturated monomers,

where the sum of A) to F) is 100% by weight, 5 to 100% of the polymerized present acid groups in with aliphatic amines or with Ammonia neutralized form are present, so that the content of the copolymers anionic, salt-like groups corresponds to the information given above.

The polymerized unsaturated acids A) and optionally F) are, as stated, at least partially neutralized, so that the resulting anionic groups the solubility or dispersibility of the copolymers in Ensure or at least lighten water. In the case of only Low concentrations of salt-like groups can cause solubility or disper Greedability of the copolymers in water by using external emuls gators be relieved. In any case, the water dilutability of the Copo lymerisate either as a dispersion or colloidal to molecularly disperse "solution" to be guaranteed.

The monomers B) and C) can be varied such that in total B) + C) from 10 to 85% by weight, only one of the monomers is present, in which case Styrene is preferred.

Examples of suitable C _1-8 -alkyl acrylates D) are methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, n-hexyl acrylate, n-octyl acrylate and 2-ethylhexyl acrylate. Preferred are n-butyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, in particular n-butyl and / or 2-ethylhexyl acrylate.

Examples of suitable C _2-8 alkyl methacrylates D) are ethyl methacrylate, n-butyl methacrylate and / or 2-ethylhexyl methacrylate.

Examples of suitable hydroxyl-functional (meth) acrylates E) are 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxyisopropyl (meth) acrylate,  4-hydroxybutyl (meth) acrylate or any mixture of these monomers. 2-Hydroxyethyl methacrylate and the technical mixture are preferred 2-hydroxypropyl and 2-hydroxyisopropyl methacrylate, commonly called Hydroxy-propyl methacrylate called.

The further monomer units F) can be substituted styrene derivatives, such as, for example, the isomeric vinyl toluenes, α-methylstyrene, propenylbenzene, C ₅ -C ₁₂ cycloalkyl (meth) acrylates, isobornyl (meth) acrylate, vinyl esters such as vinyl acetate, propionate or versatate, vinyl sulfonic acid be, the total amount of polymerizable acids ((carboxylic acids A) plus, where appropriate, the acids mentioned under F) does not exceed 7% by weight.

For at least partial neutralization of the acid present as a copolymer Groups come ammonia or aliphatic amines such as Triethyla minute Dimethylethanolamine, diethylethanolamine, triethanolamine or any other their aliphatic amines, preferably in the molecular weight range 31 to 200, in Consideration.

The copolymers a) can be prepared, for example, according to the principle of Solution polymerization in organic solvents. Appropriate solution Medium are, for example, toluene, xylene, technical mixtures of alkyl aromatics (Solvesso 100, Solvesso 150 etc.), chlorobenzene, ethyl or butyl acetate, Methyl or ethyl glycol acetate, methoxypropylacetate, methoxybutyl acetate, butylglycol, Dioxane, ethylene glycol mono- or diethyl ether, dipropylene glycol dimethyl ether, Acetone, butanone, methylene chloride or any mixture of such solvents.

When the copolymers a) are prepared in solution, generally such Solvents and used in such low concentrations that a removal tion of the same after completion of the polymerization and transfer to the aqueous Phase is not required.  

As a polymerization initiator of this radical solution polymerization come, for. B. aliphatic azo compounds such as azoisobutyronitrile (AIBN) or peroxidic Connections, e.g. B. benzoyl peroxide, tert-butyl peroctoate, tert-butyl perpivalate, tert-butyl perbenzoate or di-tert-butyl peroxide in question.

As molecular weight regulators come especially sulfur compounds, such as. B. Dodecyl mercaptan (dodecanethiol) or thioglycol.

After the polymerization has ended, the solutions or dispersion are prepared nen a) preferably such that the organic polymer solution directly with Neu Tralisationsamin added and then introduced into the aqueous phase or the organic polymer solution in the water phase provided with neutralizing agent metered and homogenized. If necessary, this can be done during the polymerization then partially or completely cover current organic solvents be breastfeeding.

However, the preparation of the copolymers a) directly in is particularly advantageous aqueous dispersion by the process of emulsion polymerization. As a radical Starters come here in particular peroxodisulfates, for. B. potassium or ammonium peroxodisulfate. In the preparation of the copolymers a) after The principle of emulsion polymerization can also be used with external emulsifiers such as for example anionic, such as those based on alkyl sulfate, alkylarylsulfonates, alkyl phenol polyether sulfates such. B. in Houben-Weyl, methods of organic Che mie, expansion and follow-up volumes, 4th edition, volume E 20, 1987 (part 1, pages 259 to 262) or alkyl polyether sulfates, or nonionic emulsifiers, such as z. B. the alkoxylation, especially ethoxylation products of alkanols, Phe nols or fatty acids are used, which are subsequent to the preparation of the Copolymers remain in the system and are regarded as auxiliaries c) can. If such emulsifiers are present, one is often sufficient very low neutralization of the acid groups present to ensure the Homogeneity of the solutions or dispersions a). The at least in less  Concentration neutralizing agents can already select the system be incorporated during the emulsion polymerization. These dispersions have general solids contents of 20 to 60% by weight, pH values of 6 to 10, visco tities from 10 to 5000 mPa.s and average particle diameters from 50 to 300 nm (measured with laser correlation spectroscopy). Glass temperatures (determined by means of DSC) of the solid resins are above 20 ° C, preferably above 40 ° C.

Polyisocyanates suitable as component b) are, in particular, the so-called "Lacquer polyisocyanates" with aromatic or (cyclo) aliphatic bound Isocya natgruppen, the latter (cyclo) aliphatic polyisocyanates particularly are preferred.

For example, "paint polyisocyanates" based on hexame are very suitable ethylene diisocyanate or 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclo hexane (IPDI) and / or bis (isocyanatocyclohexyl) methane, especially those which are based exclusively on hexamethylene diisocyanate. Under "Lackpolyisocya naten "based on these diisocyanates are the known biuret, urethane, Derivatives of these containing uretdione, allophanate and / or isocyanurate groups To understand diisocyanates, which after their preparation in a known manner, preferably by distillation of excess starting diisocyanate to a residual content of less than 0.5% by weight has been exempted. To the preferred th aliphatic polyisocyanates to be used according to the invention belong to the Polyisocyanates containing the above-mentioned criteria and having biuret groups based on hexamethylene diisocyanate, such as those used in the process can be obtained, which are described in US-A 3 124 605, US-A 3 358 010, US-A 3 903 126, US-A 3 903 127 or US-A 3 976 622 and which are composed of mixtures of N, N ', N "-Tris- (6-isocyanatohexyl) biuret with minor amounts of its height ren homologues exist, as well as the cy clical trimer of hexamethylene diisocyanate, as described in US Pat. No. 4,324,879 can be obtained, and essentially from N, N ', N "-Tris- (6-isocyanato hexyl) isocyanurate in a mixture with minor amounts of its higher Ho  mologists exist. The criteria mentioned are particularly preferred mixtures of uretdione and / or isocyanurate poly Isocyanates based on hexamethylene diisocyanate, as described by catalytic oils Gomerization of hexamethylene diisocyanate using trialkylphos phines arise. The last-mentioned mixtures are particularly preferred Viscosity at 23 ° C from 50 to 500 mPa.s and between 2.2 and 5.0 NCO functionality. However, the use of monomeric polyisocya is also possible names such as B. 4-isocyanatomethyl-1,8-octane diisocyanate.

In the case of the aromati which are likewise suitable according to the invention but are less preferred The polyisocyanates in question are, in particular, "paint polyisocyanates" Base of 2,4-diisocyanatotoluene or its technical mixtures with 2,6-diiso cyanatotoluene or based on 4,4'-diisocyanatodiphenylmethane or its Ge mix with its isomers and / or higher homologues. Such aromatic Lacquer polyisocyanates are, for example, the urethane groups containing Isocya nate, as by the reaction of excess amounts of 2,4-diisocyanatotolu oil with polyhydric alcohols such as trimethylolpropane and subsequent distilla tive removal of the unreacted excess diisocyanate can be obtained. Other aromatic lacquer polyisocyanates are, for example, the trimerizates from monomeric diisocyanates mentioned by way of example, d. H. the corresponding isocyanato isocyanurates, which are also preferably distilled following their preparation have been freed from excess monomeric diisocyanates.

In principle, it is of course also possible to use unmodifi graced polyisocyanates of the type mentioned by way of example, if these are made Correspond to statements regarding viscosity.

The preferred use of hydrophilized polyisocyanates b) by non-ionic or anionic hydrophilization of the above-mentioned hydrophobic Polyisocyanates have been prepared is described above.  

The polyisocyanate component b) can otherwise from any mixtures of polyisocyanates mentioned as examples.

The two-component PU mixtures to be used according to the invention are produced generally by simply stirring the individual components a) and b) to ma nual way or by the action of a stirrer or in the case of difficult to disperse 2K systems with a nozzle jet disperser, the proportions so ge be chosen that NCO / OH equivalent ratios of 0.2: 1 to 5: 1, preferred wise 0.7: 1 to 3: 1, result.

In principle, it is already possible to use the nonionic surfactant component a1) before or during the polymerization of a). If component a1) the polyol component a) already before the polymerization, the Addition in the case of emulsion polymerization already in the aqueous receiver in generally together with an anionic emulsifier.

If component a1) is used during the feed polymerization, this is done the addition generally to the incoming monomer mixture or in the case sufficient Water dispersibility to the aqueous feed initiator solution. In principle, it is also possible to add surfactant component a1) to the polyol Component a) after the polymerization has ended.

The compatibility between the polyisocyanate component b) and the polyolcoma component a) and thus also the easier dispersibility of the resulting from this compo The aqueous 2K-PUR system produced is considerably increased if the Polyisocyanate component either nonionically or anionically hydrophilized wor that is. The dispersion can then be done manually or with simple ones Agitators such. B. a dissolver.  

The mixtures of a) and b) to be used according to the invention or those of their Individual components used in the manufacture and additives c) of the coating technology are incorporated.

These include, for example, additional amounts of water and / or solvent to adjust the suitable processing viscosity of the invention coating agents. In the ready-to-use coating according to the invention based on the total weight of all components, mean 2 to 25% by weight of organic solvents and 10 to 75% by weight Water before. Other auxiliaries and additives c) are, for. B. pigments, fillers, ver solvents, thickeners, defoamers, deaerators and the like.

The coating compositions according to the invention can be used in all technically customary ways Methods such as B. spraying, dipping or painting on any surface such as z. B. wood, metal, plastic or mineral substrates as a substrate worn and dried at room temperature up to approx. 80 ° C. Especially before the application is on wood.  

Examples Polyisocyanate 1

Desmodur® N 100 (Bayer AG, Leverkusen, DE) is a non-hydrophilically modified Polyisocyanate based on 1,6-diisocyanatohexane with an NCO content of approx. 22.0%, an average NCO functionality of approx.3.8, a viscosity of approx. 10000 mPa.s (23 ° C) and an NCO equivalent weight of approx. 191 g / mol. follow de components were incorporated into this polyisocyanate: to 70 parts by weight of the 100% polyisocyanate 7 parts by weight of the emulsifier Rhodafac® RE 610 (Rhone Poulenc Chemicals), 1 part by weight of triethylamine and 22 parts by weight of methoxybutyla acetate.

Polyisocyanate 2

850 g (4.39 eq) of an isocyanurate group-containing polyisocyanate based on 1,6-diisocyanatohexane (HDI) with an NCO content of 21.7%, an average NCO functionality of 3.5 (according to GPC), one The monomeric HDI content of 0.1% and a viscosity of 3000 mPa.s (23 ° C) are introduced at 100 ° C under dry nitrogen and stirring, within 30 min with 150 g (0.30 val) egg nes started on methanol, monofunctional polyethylene oxide polyether with an average molecular weight of 500, corresponding to an NCO / OH equivalent ratio of 14.6: 1, and then stirred at this temperature until the NCO content of the mixture after about 2 h to one full urethanization corresponding value of 17.2% has fallen. The allophanatization reaction is started by adding 0.01 g of zinc (II) -2-ethyl-1-hexanoate. The temperature of the reaction mixture rises to 106 ° C. due to the heat of reaction released. After the exotherm subsided, about 30 minutes after the addition of catalyst, the reaction was stopped by adding 0.01 g of benzoyl chloride and the reaction mixture was cooled to room temperature. There is a practically colorless, clear polyisocyanate mixture with the following characteristics:
Fixed salary: 100%
NCO content: 16.0%
NCO functionality: 4.0
Viscosity (23 ° C): 3200 mPa.s
Polyisocyanate 2 is used as a 70% by weight solution in methoxybutyl acetate.

Polyisocyanate 3

970 g (5.00 eq) of an isocyanurate group-containing polyisocyanate based on 1,6-diisocyanatohexane (HDI) with an NCO content of 21.7%, an average NCO functionality of 3.5 (according to GPC), one The monomeric HDI content of 0.1% and a viscosity of 3000 mPa.s (23 ° C.) together with 30 g (0.14 val) of 3- (cyclohexylamino) propanesulfonic acid, 17.4 g (0.14 mol ) Dimethylcyclohexylamine and 254 g of 1-methoxypropyl-2-acetate stirred under dry nitrogen at 80 ° C for 5 hours. After cooling to room temperature, there is a practically colorless, clear solution of a polyisocyanate mixture according to the invention with the following characteristics:
Fixed salary: 80%
NCO content: 16.0%
NCO functionality: 3.4
Viscosity (23 ° C): 570 mPa.s
Color number: 15 APHA
Sulphonate group content: 0.9%.

All examples 1-12 are so-called primary dispersions, which - ab seen from the use of surfactants a1) according to the invention - analogously to Examples 1 and 2 of EP-A 0 557 844 were synthesized.

Polymer polyol 1 (Primary dispersion as a comparative example without nonionic surfactant)

This vinyl polymer polyol primary dispersion is based on the following comonomer mixture:
Acrylic acid (3.0% by weight), methacrylic acid hydroxypropyl ester (16.9% by weight), methacrylic acid methyl ester (50.0% by weight) and acrylic acid n-butyl ester (28.1% by weight), polymerized in Presence of the emulsifier Agitan® 951 (Bayer AG, Leverkusen, DE) (ammonium salt of dodecyltriethylene oxide monosulfate; approx. 2.0% by weight based on the monomer mixture). The following physico-chemical characteristics are obtained:
Solids content: 42.0% by weight
pH: 7.5
Viscosity (23 ° C; D = 42 s ^-1 ): 400 mPa.s
average particle diameter (LKS): 93 nm
Acid number: 12.4 mg KOH / g dispersion
Glass temperature Tg: 55 ° C.

Polymer polyol 2 (Comparative example analogous to example 1 with added nonionic surfactant)

The polymer polyol was prepared as in the example of polymer polyol 1; after the polymerization had ended, however, it became a nonionic polyethylene lenoxide / propylene oxide block polymer with a molecular weight of 2090 g / mol and an ethylene oxide content of 10% (Synperonic® PE / L61 (ICI Surfactants); approx. 2 wt .-% based on the dispersion) of the finished dispersion. This Dispersion has similar physical and chemical characteristics as polymer polyol 1 on.

Polymer polyol 3 Vinyl polymer polyol dispersion based on the following comonomers

Acrylic acid (3.0% by weight), methacrylic acid hydroxypropyl ester (16.9% by weight), styrene (68.4% by weight) and acrylic acid n-butyl ester (9.7% by weight) polymerized in counter were the same emulsifier (approx. 2.0% by weight with respect to the monomer mixture) as with polymer polyol 1 and with the addition of the same polyethylene oxide / polypropylene oxide block polymer as in example 2 (Synperonic® PE / L61 (ICI surfactants); approx. 2% with respect to the Dispersion) in the polymer template. The dispersion has the following physico-chemical characteristics:
Solids content: 43.9% by weight
pH: 7.0
Viscosity (23 ° C; D = 42 s ^-1 ): approx. 80 mPa.s
average particle diameter (LKS): 91 nm
Acid number: 12.8 mg KOH / g dispersion.

Polymer polyol 4 (Primary dispersion)

Vinyl polymer polyol dispersion based on the same comonomers as for poly merpolyol 3; Production also in the presence of the same emulsifier as for Po lymerpolyol 1. During the feed polymerization, the feed monomer blend with the block polymer Synperonic® PE / L61 (ICI surfactants; approx. 2% with respect to the dispersion).

The following physico-chemical characteristics are obtained:
Solids content: 43.6% by weight
pH: 7.2
Viscosity (23 ° C; D = 42 s ^-1 ): 90 mPa.s
Acid number: 13.9 mg KOH / g dispersion
average particle diameter (LKS): 102 nm.

Polymer polyol 5 (Primary dispersion as a comparative example for a polyol with Addition of a nonionic surfactant)

Vinyl polymer polyol dispersion based on the same comonomers as for poly merpolyol 3; Production also in the presence of emulsifier 951 (ammonium salt of dodecyl triethylene oxide monosulfate; approx. 2.0% by weight based on monomer mixture); after the polymerization has ended, the dispersion becomes neutral sation with ammonia with the polyethylene oxide / polypropylene oxide block polymer Synperonic® PE / L61 (approx. 2% with regard to dispersion) added.

The following physico-chemical characteristics are obtained:
Solids content: 43.2% by weight
pH: 7.5
Viscosity (23 ° C; D = 42 s ^-1 ): approx. 70 mPa.s
Acid number: 13.4 mg KOH / g dispersion
average particle diameter (LCS): 75 nm
Molecular weight Mn [g / mol]: 23300
Molecular weight Mw [g / mol]: 581000
Glass temperature (DSC): 81 ° C.

Polymer polyol 6

Vinyl polymer polyol dispersion based on the same comonomers as in poly merpolyol 3; Production likewise in the presence of the same emulsifier as for polymer polyol 1. In addition, a polyethylene oxide / polypropylene oxide block polymer with a molecular weight of 2200 g / mol and an ethylene oxide content of 40% (Synperonic® PE / L44 (ICI surfactants); approx . 2% based on the dispersion). The aqueous dispersion has the following physico-chemical characteristics:
Solids content: 43.4% by weight
pH: 7.2
Viscosity (23 ° C; D = 42 s ^-1 ): <100 mPa.s
Acid number: 13.3 mg KOH / g dispersion
average particle diameter (LKS): 110 nm.

Polymer polyol 7

Vinyl polymer polyol dispersion according to EP-A 0 358 979 based on the same comonomers as in polymer polyol 3; Production also in the presence of the same emulsifier as for polymer polyol 1. A polyethylene oxide / polypropylene oxide block polymer with a molecular weight of 2900 g / mol and an ethylene oxide content of 40% (Synperonic® PE / L64, ICI surfactants; approx. 2% with respect to the dispersion) used. The aqueous dispersion has the following physico-chemical characteristics:
Solids content: 43.4% by weight
pH: 7.1
Viscosity (23 ° C; D = 42 s ^-1 ): <100 mPa.s
Acid number: 12.9 mg KOH / g dispersion
average particle diameter (LKS): 125 nm.

Polymer polyol 8

Vinyl polymer polyol dispersion based on the same comonomers as for poly merpolyol 3; Production also in the presence of the same emulsifier as for Po lymerpolyol 1. In the template is also a polyethylene oxide / polypropylene oxide block polymer with a molecular weight of 3800 g / mol and one  Ethylene oxide content of 10% (Synperonic® PE / L101 (ICI Surfactants); approx. 2% be regarding the dispersion) used.

The aqueous dispersion has the following physico-chemical characteristics:
Solids content: 43.2% by weight
pH: 7.0
Viscosity (23 ° C; D = 42 s ^-1 ): <100 mPa.s
Acid number: 12.8 mg KOH / g dispersion
average particle diameter (LKS): 93 nm.

Polymer polyol 9

Vinyl polymer polyol dispersion based on the same comonomers as for poly merpolyol 3; Production also in the presence of the same emulsifier as for Po lymerpolyol 1. In the template is also a polyethylene oxide / polypropylene oxide block polymer with a molecular weight of 4800 g / mol and one Ethylene oxide content of 80% (Synperonic® PE / F38 (ICI Surfactants); approx. 2% be regarding the dispersion) used.

The aqueous dispersion has the following physico-chemical characteristics:
Solids content: 43.8% by weight
pH: 6.7
Viscosity (23 ° C; D = 42 s ^-1 ): <100 mPa.s
Acid number: 13.0 mg KOH / g dispersion
average particle diameter (LKS): 133 nm.

Polymer polyol 10

Vinyl polymer polyol dispersion according to Example 3, prepared in the presence of the same ben emulsifier. An ethylene oxide / propylene oxide Block polymer based on ethylenediamine as a starter and a molecular weight of 3700 g / mol and an ethylene oxide content of 10% (Synperonic® T / 701 (ICI surfactants); about 2% with respect to the dispersion).

The aqueous dispersion has the following physico-chemical characteristics:
Solids content: 43.6% by weight
pH: 7.5
Viscosity (23 ° C; D = 42 s ^-1 ): <100 mPa.s
Acid number: 13.8 mg KOH / g dispersion
average particle diameter (LKS): 105 nm.

Polymer polyol 11

Vinyl polymer polyol dispersion according to Example 3, prepared in the presence of the same ben emulsifier. In addition, a template started on a fatty alcohol is placed in the template Polyether with the approximate molecular weight 630 g / mol (Synperonic® LF / RA30 (ICI surfactants); about 2% with respect to the dispersion).

The aqueous dispersion has the following physico-chemical characteristics:
Solids content: 44.5% by weight
pH: 8.5
Viscosity (23 ° C; D = 42 s ^-1 ): <100 mPa.s
Acid number: 14.2 mg KOH / g dispersion
average particle diameter (LCS): 95 nm.

Polymer polyol 12

Vinyl polymer polyol dispersion consisting of the same comonomers as in Bei game 1 in the same weight ratios, made in the presence of the same emul gators as for polymer polyol 1. The same nonioni is additionally added to the template The same surfactant as used for polymer polyol 2 (Synperonic® PE / L61; approx. 2% be regarding the dispersion).

The aqueous dispersion has the following physico-chemical characteristics:
Solids content: 43.6% by weight
pH: 7.5
Viscosity (23 ° C; D = 42 s ^-1 ): 150 mPa.s
Acid number: 14.5 mg KOH / g dispersion
average particle diameter (LKS): 121 nm.

Application engineering examples Examples 1-6

Examples 1-6 are polymer example 12 and the polymer comparison Examples 1 and 2 with regard to the incorporation of polyisocyanates 1 and 2 under examined.

First, pigment pastes were produced from these 3 polymer dispersions. To first the polymer dispersions were treated with Disperbyk® 190 and BYK® 024 (both Byk Chemie, Wesel, DE) and the Tronox® R-KB-2 (Kerr McGee Pigments GmbH, Krefeld, DE) and Aerosil® 200 (Grace, DE) dispersed using a dissolver. The mixture was redispersed at 2000 rpm for about 15 minutes.

A) pigment pastes

With these pigment pastes 6 varnishes according to the following table for formulated. These lacquers were coated with a box knife in a wet film thickness of approx. 200 µm on an Erichsen test card and ge 24 h at 18-24 ° C dries. The gloss (angle 60 °) was then determined [value 1: black zer carton / value 2: white carton].  

B) Lacquer formulation

Examples 1 and 4 show that the installation of the nonio African surfactants into the polyol dispersion, the incorporation of polyisocyanates significantly improved and thus a significant increase in gloss compared to the 2K systems 2, 3, 5 and 6 not caused according to the invention.  

Examples 7-10

In this test series, polymer example 3 was compared with polymer comparison 5 in pigmented coating systems with regard to chemical resistance in accordance with DIN 68861. The lacquers were produced in accordance with Examples 1-6.

These examples show that the nonioni tensides a significant improvement in chemical resistance, especially against coloring liquids, is achieved (rating 0: very chemical bil; 5: completely unstable).

Examples 11-17

In this series of experiments, clearcoat systems are produced from polymer dispersions 3 and 6-11 and tested for gloss formation and chemical resistance in accordance with DIN 68861.

The hardener was dispersed in for 2 minutes at about 2000 rpm using a dissolver. After that were wet films in a layer thickness of 150 microns on an MDF board with is coated with a melamine resin film. First, the test area Predried for 15 min at approx. 20 ° C, then hardened for 60 min at 60 ° C and for another 7 days stored at approx. 20 ° C. The chemical resistance was tested in accordance with DIN 68861.

Note: if 2 measured values are listed, the 1st value means an immediate assessment division and the 2nd value the assessment after 3 days.

This paint was also applied to a test card with a wet film thickness of 200 µm pulled up and after 24 h (storage at approx. 20 ° C), the degree of gloss (with egg angle of 60 °).

This series of experiments shows that with the OH-containing dispersion according to the invention high-gloss coating systems with excellent chemical resistance will hold.

Example 18

Lacquers were produced according to Example 9 and applied to foiled MDF boards using an airless system (2-component system from Graco). Application tests were carried out with the following nozzle combinations:
Example of use 1: spray nozzle (0.32 mm); no pre-atomizing nozzle
Example of use 2: spray nozzle (0.32 mm); Pre-atomizer nozzle (0.38 mm)
Example of use 3: spray nozzle (0.32 mm); Pre-atomizer nozzle (0.28 mm)
Example of use 4: spray nozzle (0.32 mm); Pre-atomizer nozzle (0.23 mm).

The paints were applied in a wet film thickness of approx. 200 g / m ² , predried for approx. 30 min at 22 ° C. and post-cured for approx. 1 h at approx. The appearance of these coatings was assessed.

While the application examples 1 and 2 to matte and uneven loading application example 4 showed a high-gloss finish and even coating. Application example 3 showed a comparison for application example 4 a slight deterioration. This application example games show that the dispersions of the invention on a conventional 2K spraying system using simple pre-atomizing nozzles, the smaller one Have opening than the spray nozzle, can be applied in a practical manner.

Claims (15)

1. Aqueous 2K-PUR varnishes, characterized in that their binders are made of

• a) vinyl polymer polyol type dispersions,
• b) polyisocyanates and
• c) usual additives for water-based paint technology

consist of
the polyol dispersions a)
Hydroxyl numbers between 10 and 264 mg KOH / g solid resin, acid numbers between (calculated on the sum of the neutralized and non-neutralized acid groups) from 0 to 55 mg KOH / g solid resin, molecular weights M _n of at least 5000 g / mol or M _w of at least 30000 g / mol, glass temperatures of at least 20 ° C and average particle diameter of at most 300 nm and in the presence of

• 1. 0.1 to 10.0% by weight, based on the sum of the solids contents of polymer polyol and polyisocyanate, of nonionic surfactants of the polyether type have been prepared,

the polyisocyanates b)
Viscosities of at most 12000 mPa.s and either non-hydrophilized or nonionic or anionically hydrophilized character, and where component a) is added to component a) in an amount which corresponds to an equivalent ratio of isocyanate groups of component b) to hydroxyl groups of the component a) from 0.2: 1 to 5: 1. 2. Paints according to claim 1, characterized in that component a) in the presence of 1.0 to 8.0% by weight of the nonionic surfactant of the polye thertyps a1) was produced. 3. Varnishes according to claims 1 and 2, characterized in that block polymers of ethylene oxide and propylene oxide of the type according to formula (I) were used as non-ionic surfactant components a1):
4. Paints according to claims 1 and 2, characterized in that block and statistical ethylene oxide / propylene oxide copolymers based on fatty alcohol are used as non-ionic surfactant components a1). 5. Paints according to claims 1 and 2, characterized in that block polymers of propylene oxide and ethylene oxide are used as nonionic surfactant components a1) on ethylene diamine of the type according to formula (III):
6. Paints according to claims 1 and 2, characterized in that as nonio African surfactant component a1) adducts of polyethylene oxide with fatty alcohols be used. 7. Paints according to claims 1 and 2, characterized in that as nonio African surfactant components a1) polyether / polyester block copolymers be set. 8. Paints according to claims 1 to 6, characterized in that the non -io African surfactants have an ethylene oxide content of 5 to 80% by weight, molecular weights up to 10000 g / mol and hydroxyl contents from 0.3% by weight to 8.0% by weight point.   9. Paints according to claims 1 to 8, characterized in that the nonio African surfactant a1) during the preparation of the polymer polyol dispersion a) was added. 10. Paints according to claims 1 to 8, characterized in that the nonio African surfactant a1) before the production of the polymer polyol in the polymer tion template was used. 11. Paints according to claims 1 to 10, characterized in that the polyi socyanate (b) non-hydrophilized, non-water-dispersible polyi are socyanate. 12. Paints according to claims 1 to 10, characterized in that as a polyiso cyanate (b) nonionic, hydrophilized with a polyether monoalcohol Polyisocyanates were used. 13. Paints according to claims 1 to 10, characterized in that as a polyiso cyanate (b) anionically hydrophilized polyisocyanates were used.   14. Varnishes according to claim 13, characterized in that anionic hydrophilized polyisocyanates are used as polyisocyanates (b) which contain phosphate groups with 0.2 to 5.0% by weight, based on the sum of the solids contents of polymer polyol and polyisocyanate Surfactants with the following structures have been hydrophilized:
n = 1-100; p = 5-20; r = 5-15; M = alkali or (subst.) Ammonium ion. 15. Varnishes according to claim 13, characterized in that the polyisocy anate (b) uses anionically hydrophilized polyisocyanates, the sulfonate group Pen included in chemically built-in form. 16. Use of paints according to claims 1 to 14 for painting Wood, metal, plastic and mineral substrates.